We also evaluated our system using real data. The setup consisted of 12 (\(m=12\) ) omni-directional microphones (the T-bone MM-1) spanning a volume of \(4.0 \times 4.6 \times 1.5\)  meters.
A speaker was moved through the setup while emitting sound.
Ground truth positions for the microphones and speaker positions were found using a Qualisys motion capture system.
The microphones were all internally synchronized, but we assume that the time of sound emission from the speaker is unknown. We use the position estimation of the sound sources from the Qualisys system. Consequently, the microphone positions and emission times correspond to the situation of unknown receivers and offsets, while the sender positions are assumed to be known. In the experiment a song was played through the speaker and the arrival times \(t_{ij}\)  were found using GCC-PHAT [1]}. This resulted in a total of \(n=151\)  sound events with available pseudoranges. Next, we sampled 4 receivers and 5 transmitters and solved the problem using our \(4r/5s\)  solver. Finally, we solved the remaining offsets as described above and trilaterated the remaining receivers. This estimate was further finalized using Levenberg-Marquardt algorithm. As a final result, the mean position error for the receivers was \({10}{}\) .
